Purification of Free DHA by Selective Esterification of Fatty Acids from Tuna Oil Catalyzed by <i>Rhizopus oryzae</i> Lipase
Bibliographic record
Abstract
Abstract Tuna fish oil contains 25–30 % docosahexaenoic acid (DHA) and is one of the richest sources of DHA. The present paper investigates the enrichment of DHA by selective esterification of fatty acids obtained from hydrolysis of tuna fish oil catalyzed by Rhizopus oryzae lipase (ROL). The fatty acid mixture obtained after hydrolysis of tuna fish oil, referred to as tuna‐FFA contained 26 % DHA. For purification/concentration of DHA in free fatty acids, selective esterification of the fatty acid mixtures with butanol was carried out using ROL in a water‐organic solvent system. The best reaction parameters found in this study were pH 7, temperature 35 °C, agitation speed 800 rpm and a fatty acid to solvent (iso‐octane) ratio of 1:1.32 (w/v). Also, the effects of other parameters such as type of alcohol, type of enzyme, alcohol to fatty acid ratio, enzyme to fatty acid ratio were studied to determine the most suitable reaction conditions. Exactly 76.2 % of tuna‐FFA was esterified in 24 h, under the most suitable reaction conditions and the DHA content in the fatty acid fraction rose from 26 to 86.9 % with 80 % recovery of DHA, after selective esterification. The DHA content of fatty acids in butyl esters was found to be 13.6 %.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".